1. Field of the Invention
The invention broadly pertains to a means for positioning, spacing and securing reinforcing steel in a concrete structural member.
More particularly, the invention is directed to a spacer member which is particularly adapted to effectively locate and restrain reinforcing steel bars in a concrete structural member having a generally circular cross-section, such as a round or circular column. The spacer member is specifically and uniquely adapted to accommodate a variety of design requirements and specifications, being suited for locating the requisite number and size of steel bars at the requisite locations in a particular structural member. When supported by means of the subject spacer member as contemplated by the invention, the reinforcing bars are positively restrained from undesirable shifting which is apt to occur with conventional devices during placement of the concrete.
A critical element of reinforced concrete design involves the accurate placement and support of the reinforcing bars in the concrete structural member. It is essential that the reinforcing steel be precisely located and supported the required distance inside the face of the concrete. Failure to maintain the reinforcing steel a sufficient distance, generally 11/2 inches, inward of the face of the concrete results in detrimental oxidation of the steel reinforcement, thereby significantly compromising the integrity of the structural member and necessitating exceedingly costly and extensive restoration of the structure. The support member of the instant invention addresses and eradicates the normally prevalent problem of oxidation associated with reinforced concrete members by insuring accurate location of the steel reinforcement the optimum distance inside the face of the concrete.
The detrimental effects of oxidation can only be entirely prevented when the reinforcing steel is not only accurately positioned inside the concrete face, but when the reinforcing steel is also restrained from axial, transverse and rotational movement during placement of the concrete, so as to prevent unwanted shifting of the steel from its required position. The spacer member of the present invention is uniquely capable of obtaining effective and consistent placement of the steel the necessary distance inside the face of the concrete and of maintaining the steel in its allocated position.
Moreover, insuring the integrity of a concrete structural member demands that the reinforcing steel bars be successfully and reliably locked in position within the concrete form with respect to each other and prohibited from shifting from the latter positions when the concrete is placed. The number of and spacing for the reinforcing bars in a particular structural member varies according to diverse engineering factors such as wind load, snow load, etc. The subject support member positively prevents undesirable and potentially damaging movement of the reinforcing steel from the design parameters established for the structural member, thereby enhancing the structural integrity of the concrete member. Consequently, the design efficiency of architects and engineers for concrete structural members in enhanced, while the potential liability for the technical designer is substantially reduced. Additionally, the attributes in design and placement of reinforcing steel realized with the present spacer member result in lower costs of construction and maintenace for reinforced concrete structures.
A further significant feature of the invention involves its impressive ease of utilization in the field by relatively unskilled personnel. Prior art methods and devices for locating reinforcing steel in round columns have proved to be unsatisfactory due to the great difficulty, unreliability and complexity associated with their use. As a result, the latter devices are problematic for many reasons, including inaccuracies and deficiencies in assembly resulting in improper positioning of the steel reinforcing bars within the form. The subject invention, in contrast, is not only simple to utilize, but also provides a continually reliable means for assuring precise positioning of the reinforcing steel.
The foregoing features are realized with the instant invention by presenting a spacer member for reinforcing steel bars, which spacer member lends itself for implementation in locating and securing steel reinforcing bars the required distance inward of the concrete form and, hence, the outside face of the concrete. Furthermore, the spacer member provides means for spacing the steel bars with respect to each other within the concrete form. The invention is advantageous for its unprecedented reliability, feasibility, simplicity and economy, and is adapted to be formed so as to accommodate a variety of sizes and spacing schemes for the reinforcing steel in accordance with diverse technical specifications.
2. Description of the Prior Art
It is known in the prior art to provide reinforcing means in a generally cylindrical concrete structural member, such as a column. For example, U.S. Pat. No. 1,085,042 to Hickson discloses a post member wherein are located reinforcing rings connected by upright ties. Similarly, U.S. Pat. No. 1,412,096 to Von Emperger shows a compression member comprising a tube surrounded by an envelope of hooped concrete having helical windings and longitudinal reinforcing bars.
The prior art further teaches means for spacing and positioning longitudinal members in a generally vertical cylindrical structural member. An example of the latter teaching is disclosed in U.S. Pat. No. 1,248,049 to Wunder. Wunder teaches a column plate which is adapted to be provided at the top of a column for holding, among other things, column rods, service pipes and water pipes.
Means for spacing and locating vertical reinforcing bars in a round concrete column are also known in the prior art. For instance, U.S. Pat. No. 1,699,736 illustrates a spacer member in the form of a "spider", and including a plurality of prongs which project radially from annular hollow frame portions, and a plurality of circular cavities for receiving steel reinforcing bars. The bars are adapted to be retained within the cavities of means of lugs, which are located on each side of each cavity, being bent together around the respective rod.
U.S. Pat. No. 3,292,334 to Stober similarly discloses a wheel-like spacer member including a rim and a hub, with reinforcing rods adapted to be received in gaps defined by the respective member.
Finally, U.S. Pat. No. 1,817,437 to Hawkinson discloses a spacer for a reinforced concrete pole comprising a plurality of flat triangular-shaped pieces of metal, each having long lugs adapted to be wrapped around a helical wrapping wire 2. Additional lugs disposed between the long lugs are provided to be bent into engagement with a reinforcing rod. The helical wrapping and the reinforcing rods are intended to be fastened together by lighter wire.
It is apparent from the foregoing that the prior art fails to teach or suggest a unitary spacer member which is able to accommodate a range of design parameters, and which is highly and consistently accurate, reliable and easy in its assembly and use as contemplated by the instant invention.